Documentation: spelling corrections

Some spelling corrections

Documentation/doc/Documentation/Developer_manual/Chapter_iterators_and_circulators.txt

@@ -42,7 +42,7 @@ Thus we will not give a full description of these concept here
 but only a few hints about how to use and write handle, iterators and circulators in \cgal.  Developers should consult the above-mentioned references to become
 familiar with the iterator, circulator and handle concepts. In
 particular,  the notions of iterator and circulator ranges,
-dereferencable and past-the-end values,
+dereferenceable and past-the-end values,
  mutable and constant iterators and circulators,
 and the different categories (forward, bidirectional, random-access, etc.)
 of iterators and circulators, are fundamental.

Documentation/doc/Documentation/Developer_manual/Chapter_portability.txt

@@ -57,14 +57,14 @@ is used only internally.  Requirements are lower for code that
 is not released such as the test-suite. Boost libraries already accepted
 in the C++ Standard Library Technical Report will be the first easy
 candidates (these are marked <TT>[TR1]</TT> in the list below). However,
-wrapping the use within \cgal is generally adviced (like what is done
+wrapping the use within \cgal is generally advised (like what is done
 in the `cpp11` namespace).
 Finally, the policy is that if a better alternative exists in Boost and is
 allowed, then \cgal code must use it instead of a \cgal version (which
 probably must be deprecated and phased out), trying not to break backward
 compatibility too much.
 
-A list of reasonnable Boost libraries to use in the \cgal API is
+A list of reasonable Boost libraries to use in the \cgal API is
 Graph, Optional, Parameter (for packages already using it),
 Property Map, Smart Pointers (for packages already using it),
 Variant.

Documentation/doc/Documentation/Developer_manual/developer_manual.txt

@@ -2,7 +2,7 @@
 
 \page dev_manual Developer Manual
 
-The developer manual is primarly aimed at \cgal developers, but may also be interesting to any \cgal user.
+The developer manual is primarily aimed at \cgal developers, but may also be interesting to any \cgal user.
 
 - \subpage devman_intro
 - \subpage devman_code_format

Documentation/doc/Documentation/Third_party.txt

@@ -291,7 +291,7 @@ for more information.
 
 \attention \ceres indicates that `glog` is a recommended dependency. `glog` has `libunwind` as a recommended dependency.
 On some platforms, linking with `libunwind` was responsible for an increase of the runtime of the final application.
-If you experience such an issue, we recommand to compile \ceres without `glog` support.
+If you experience such an issue, we recommend to compile \ceres without `glog` support.
 
 \subsection thirdpartyGLPK GLPK
 

Documentation/doc/Documentation/Tutorials/Tutorial_hello_world.txt

@@ -287,7 +287,7 @@ duplicate(T t)
 If you want to instantiate this function with a class `C`, this
 class must at least provide a copy constructor, and we
 say that class `C` must be a model of `CopyConstructible`.
-A singleton class does not fulfill this requirment.
+A singleton class does not fulfill this requirement.
 
 Another example is the function:
 

Documentation/doc/Documentation/Usage.txt

@@ -46,7 +46,7 @@ or to build your own project using \cgal, see Section \ref secoptional3rdpartyso
 
 \cgal can be obtained through different channels. We recommend using a package manager as
 this will ensure that all essential third party dependencies are present, and with the correct versions.
-You may also download the sources of \cgal directly, but it is then your responsability to independently
+You may also download the sources of \cgal directly, but it is then your responsibility to independently
 acquire these dependencies.
 
 The examples and demos of \cgal are not included when you install \cgal with a package manager,