Clean up some reStructuredText formatting.

This primarily involves escaping[1] the pluralizing "s" character when
it immediately follows an inline literal.

Also, fix the Thrift IDL link (no trailing backslash allowed).

[1] http://docutils.sourceforge.net/docs/user/rst/quickref.html#escaping
Merge pull request #51 from jparise/docs-cleanup

Clean up some reStructuredText formatting.