Escape both % and $ in the command line

Fixes issue #1884
Add new plugin for homebrew installed version of postgres
debian plugin: ignore alias in sudo/aptitude check
Merge pull request #1893 from jeremydt/postgres

Add new plugin for homebrew installed version of postgres
Merge pull request #1894 from codewhale/master

debian plugin: ignore alias in sudo/aptitude check
Merge pull request #1885 from eakret/termsupport-fix

Escape both % and $ in the command line
a