Add possibility to resolve partial template specializations.

Example: The class

```
template <typename T>
class Specialization<T*> {};
```

can be accessed via

```
.. doxygenclass:: Specialization< T * >
```

The white-spaces are necessary. This changeset addresses issue #113 but is far
from being complete. Still, the argument of sphinx directives must match
exactly the doxygen XML node name including white-spaces. A better solution
is needed for that.
Keeps breathe working on pre-2.7 versions of Python.

Creating sets in the form ``{'v1', 'v2'}`` is not supported before
Python 2.7. This is the only issue so far, which keeps Breathe from running
in such old environments and has been introduced in commit 55689d4a. The
form ``set(['v1', 'v2'])`` is valid for all Python versions.
Switch set to dictionary

As we're mimicing the rst directive options dictionary at that point. I
previously mistyped it as Python 2.7 set notation: {,} instead of
dictionary notation {:}.
Improve .gitignore files

To ignore some of the files/folders that have been floating around.
Add doc/example/changelog for template specialistaions

Thanks to rweickelt for the example contributed in the original github
issue.

Also started to format the changelog as recommended on
keepachangelog.com. More info is good.
Merge branch 'rweickelt-template'