BugFix/Enhancement: Custom Line context menu/GUI

The ability to draw new custom exit lines had been lost in the previous
SF Git master.  This reverts the GUI changes previously made and enhances
the results.  The former dialog is now more intuitive.  It is now possible
to (repetitively) undo line segments placed during the drawing operation
and to modify the characteristics of the line both during drawing and
subsequently.  It is also now possible to modify an existing line by adding
or removing segments also via an enhanced context menu.

Also to aide editing and drawing new lines, a bright yellow target is drawn
around the destination room!  When editing an existing line, the currently
selected custom line vertex is also drawn in yellow rather than orange so
the user knows which point will be modified if a vertex is added or
removed.  The help message used during some 2D mapper operations including
some custom line actions is now positioned centrally at the bottom of the
screen (in a somewhat smaller font size) so it no longer clashes with the
map info display.  It now also appears at the correct point in drawing
custom lines whereas previously it only appeared after the first point was
created by left clicking on the map.

A minor edit to TLUaInterpreter::addCustomLine() now adds support to all
five standard line styles available in current Qt version.

An Icon for the new dialog (custom_lines_properties.ui) has been added to
the resources file and a related icon also created for the custom_lines.ui.

Signed-off-by: Stephen Lyons <slysven@virginmedia.com>
BugFix: correct wrong cursor shape setting in part of dialog

Part of the dialog had the cursor set to be "UpArrowCursor" rather than
the desired "ArrowCursor" which cause a unstable (constantly changing size)
cursor with the version/OS-type Qt Libraries I was using.

Signed-off-by: Stephen Lyons <slysven@virginmedia.com>
Merge Prepare: Rearrange project file to make it more merge-able

In preparation for use as Pull Request #32 on:
http://github.com/Chris7/Mudlet2/mudletDev reorganise src.pro so that it
more closely matches my branch
http://github.com/Slysven/Mudlet2/mudletDev_fileLocation
which is lined up as Pull Request #31 on the same one of Chris's branch.

There should not be any change in overall functionality (the qmake'ed
Makefile should produce the same executable both before and after this
commit).

Signed-off-by: Stephen Lyons <slysven@virginmedia.com>
Tweaks: some small changes to custom line drawing code

Change the circles around custom line points when selected to be solid
instead of dotted - looks better under a wider range of room and exit
size settings.  Simplify the target drawing code to indicated the target
room of a custom exit line - also looks better.

Added code for the first segment of a custom exit line, was previously
explicitly not handled because of the extra code that it would require.

Status bar messages for various custom line exit situations extended to
cover corner cases.

NB. StatusBar is NOT currently showing on at least Qt 5.1 / GNU/Linux
platform.  A code lines or two is needed in mudlet.cpp to generate it.

Signed-off-by: Stephen Lyons <slysven@virginmedia.com>
Merge pull request #32 from SlySven/mudletDev_customExitsFixAndEnhance

BugFix/Enhancement: Custom Line context menu/GUI