Fixed a typo (it's -> its)
Fixed description of example custom filter

Example custom filter reverses the order of characters; doesn't convert a variable to lowercase.
Removed reference to a non-existent example.

No example is displayed under each the add (or any) filter at http://paularmstrong.github.com/swig/docs/#filters-add; removing the reference to such an example.
added {% spaceless %} tag support
Merge pull request #193 from potench/feature/spaceless

added {% spaceless %} tag support
Merge pull request #188 from airandfingers/patch-2

Fixed description of example custom filter
Merge pull request #187 from airandfingers/patch-1

Fixed a typo (it's -> its)