Add missed special characters to `isSpecialKeyChar`.

Fix for #393 broke `<C-{non-alpha}>` mappings (e.g. `<C-]>`).
Remove space requirement for :t/:move/:copy.

Vim doesn't require a space between `:t` and it's destination address.
Replace isAlphabetic with isLetter from Java 1.6.

IsAlphabetic was only introduced in Java SE 1.7.
Support a simple search for a single backslash.

Escaping will need to be revised though.

As reported in #394.
Add toString in TextViewerPosition for debugging.

It can be hard to track position errors when you can't see where a
Position is pointing to.
Fix line-wise selection swap for CRLF line endings

A line-wise selection includes the bottommost newline. The original
code tried to calculate the last line of the selection by trying to
skip left past this newline, but this puts us in the middle of a CRLF
newline character when using Windows endlines (causing an Eclipse
exception).

Simply recreate selection based on the swapped from / to positions.
These can be anywhere on the first and last line, but that is enough
to recreate a line-wise selection anyway.

Fixes #392.
Keep cursor near selection end on visual mode exit

Vim will keep the cursor in the very same spot when exiting visual mode
whereas Vrapper would always reset the selection to the top- and
left-most point of the selection.

Try to reset the pointer to a point nearest the end of the selection,
accounting for reverse selections.

Note that this isn't correct for visual line-wise mode as the caret
can only be drawn at the end of a selection.

Fixes #391.
TO BE AMENDED

Only comments documenting what goes wrong in the keyword parser.