re-add CAST5 ECB support (OpenSSL & CC backends). fixes #417
add cbc, cfb, ofb support to CAST5 (aka CAST128) for openssl & cc

fixes #393
add cast5 docs
remove some extra linebreaks
Added a docs section on Linux installation

This simply adds a short paragraph on what dependencies are needed on
Linux, as well as the command line to install them on Ubuntu (since
users of other distributions are more likely to know how to do it).
Added Debian mention, extra missing packages

One tends to forget than not everyone has python-dev installed :)
Added Pypy note and fixed libffi's "spelling"
Pypy is not a real word either apparently.
Changed .... lines to ~~~~ and s/Gnu\/Linux/Linux/
Merge pull request #604 from reaperhulk/cast5-cbc-and-more

CAST5 Support (ECB, CBC, CFB, OFB)
Merge pull request #606 from chrisglass/installation-ubuntu

Added a docs section on Linux installation
add CAST5 support to changelog
A few style nits in the docs
add versionadded to cast5
Merge pull request #607 from alex/docs-nits

A few style nits in the docs
Merge pull request #608 from reaperhulk/cast5-changelog

Add CAST5 support to changelog
Fix comments in padding.py to be accurate

This is not in fact O(n ** 2) because ``len(self._buffer)`` is bounded
by ``self.block_size``. This means that each ``self._buffer += x`` only copies
O(len(x)) bytes, meaning the whole thing is linear.
Fixed a missing word in the RSA docs
Also clean up this syntax
Merge pull request #610 from alex/padding-comments

Fix comments in padding.py to be accurate