Added common keyboard mappings that I felt were missing.

Added keys to both view and filtered view.
Added Control PageDown and Control End to go to end of file.
Added Control PageUp and Control Home to go to start of file.
Added F3 for searchNext and Shift-F3 for searchPrevious.

(cherry picked from commit 6a57e0ec53753ac5dbd66399798faeafe0d954ca)
Merge pull request #46 from rluiten/AddedKeymapping

Added common keyboard mappings that I felt were missing.