syntax_sensitive Swaps Key Bindings

Previously, setting syntax_sensitive to true would switch the key
binding for ctrl+h to a syntax-sensitive search. However, it would leave
ctrl+alt+h alone, leaving you with two ways to do a syntax-sensitive
search, but no way to search globally. With this change, setting
syntax_sensitive to true instead swaps the bindings, thus allowing you
to perform a global search with the alternate key combination.
Merge pull request #2 from matthewwithanm/alt-bindings

syntax_sensitive Swaps Key Bindings