Tidy up mainframe (creating a new dialog class).
Fix OptionalJSpinner having an excessive border.

Fixes issue CLIENT-66
Fixes issue CLIENT-2

Change-Id: I450fe4a6060988843caad0b22a1ac2ffad9e4c28
Depends-On: If58397d37b89c8fe6e099c47fb4d26fdc4589b49
Reviewed-on: http://gerrit.dmdirc.com/1630
Automatic-Compile: DMDirc Local Commits <dmdirc@googlemail.com>
Reviewed-by: Chris Smith <chris@dmdirc.com>

Change-Id: I052f46c59cfb19b64afbcaf2fbc02b17d1f40da6
Reviewed-on: http://gerrit.dmdirc.com/1633
Automatic-Compile: DMDirc Local Commits <dmdirc@googlemail.com>
Reviewed-by: Chris Smith <chris@dmdirc.com>

Make background opened windows respect maximised states

Fixes issue 4037

Change-Id: I2d5096ef116b5e5325eb050c51a17cab4e5b867d
Reviewed-on: http://gerrit.dmdirc.com/1154
Automatic-Compile: DMDirc Local Commits <dmdirc@googlemail.com>
Reviewed-by: Chris Smith <chris@dmdirc.com>

Change-Id: I0a41dbf8eb7e9e62eb5ec94eb54167a9a49243d4
Reviewed-on: http://gerrit.dmdirc.com/1149
Automatic-Compile: DMDirc Local Commits <dmdirc@googlemail.com>
Reviewed-by: Chris Smith <chris@dmdirc.com>

See corresponding core change for full details.

Change-Id: I6ddf872aa7073dd9306a17f6ae03c462a5898296
Reviewed-on: http://gerrit.dmdirc.com/1143
Automatic-Compile: Gregory Holmes <greg@dmdirc.com>
Reviewed-by: Gregory Holmes <greg@dmdirc.com>