Added import tag and compiler functions

Also, modified Container.setMargins to use contentsMargins property,
may be reverted later. PushButton.onclick() is now passed an instance
of the button. Setting text calls update().
Renamed several properties. Implemented SizeHints. Added lineedit
class. Dialog now inherits from Container. Added 'non-slot' utility
functions. Also added utility functions open_toplevel() and
close_parent().
Added style properties

In the process, the giveReturn function was added as a subfunction of
style.getValue and OxideStyle was given the staic method
OxideStyle.updateDict
Fixed style-properties bug

Previously, setting a style-property on a widget would set that
property for all widgets of that type, now only that widget is
affected. The bug was caused by accidental linkage of styledicts, which
was caused by mistake in OxideStyle.updateDict, which has now been
renamed to OxideStyle.combinedDict, which is more apt, considering what
it is supposed to do. It is not supposed to change either dictionary,
or create new dictionaries with references to the old, but return an
entirely new dictionary, with the combined data of the two dictionaries
passed.
Ignore this commit

This commit is just to get the GitHub application off my tail about
committing all changes before a sync.