Slightly experimental syntax refactoring for exceptions

This is to provide more universal compatibility between python versions.
Merge branch 'master' into dev
Merge branch 'master' into dev
Merge branch 'master' into dev
Add default keyword to vim highlights, fix #36

The default keyword allows colour schemes to define their own settings
for the signs DbgCurrent and DbgBreakPt.
Change map to noremap and equivalents, fix #34

Use non-recursive mapping, just in case the maps contain references to
other keys mapped by the user.
Stop detach command from hanging, fix #33

The detach command wasn't closing the server socket, so force the socket
to close and allow the calling script to end.
Prohibit breakpoint to be set on empty line, close #27

When setting a breakpoint, the contents of the line is retrieved,
trimmed (whitespace removed) and checked for length. If it is empty,
tell the user that a breakpoint cannot be set on an empty line.
Don't catch "vim.error" explicitly, fix #39

Catching vim.error raises a DeprecationWarning in python 2.6.
Fix tests for breakpoint, raising exception as in #27
Add function for parsing breakpoint sign positions, see #35

This function uses the Vim `sign place` command to list all signs, and
then reads the IDs and line numbers of all breakpoint signs, returning
them as a dictionary.
Update line breakpoints with sign positions, close #35

If a file is edited, breakpoints are updated with the new position.
The position is determined by the position of the sign in the buffer.
Move private methods to bottom of class in Ui

This is purely for ease of finding private methods.
Stop source panel opening in wrong position, fixes #40
Add command for setting options, closes #38

The :VdebugOpt command allows you to get and set option values. It
provides autocomplete, so you no longer have to remember the names of
options.
Clarify meaning in docs regarding setting of options
Fix latest version number in HISTORY file

Why did no-one tell me? Damn you all...
Update HISTORY file for version 1.3.2
Update README to mention latest version and changes