ENH: Fix problems with the layout of the tabs

This is moving to be a more homogeneous layout of all the elements, and
is going to be followed up by a phase of cleaning in the CSS
stylesheet, because at this point is very redundant and useless.
MAINT: Remove redundant classes in stylesheet

A lot of these classes were not being used, or poorly documented or
named in inconistent ways.
STY, MAINT: Cleanup of class names & unused things

Clean up the name of classes to be hyphen separated instead of being
obnoxiously long-named,

Add emperor as a prefix for elements that strongly compose the Emperor
user interface.
BUG, MAINT: Fix non-resizing menu problem

Fix a problem where the menu on the right side was not being resized
correctly, the contents would just simply dissappear.

Rename a few identifiers that had non-informative names.
BUG: Fix problem with layout

The layout wasn't displaying all the contents inside a tab's div because
the height was not set to 100%.
MAINT: Make all tables use the same class

Fixes #254
STY: Remove dead code and whitespace
BUG: Fix Invert Selected button not working

Turns out I removed the id that allows jQuery to fetch the elements
inside the table that contain the visibility information.
DOC: Add mention to the ChangeLog about cleanup
ENH: Use .format instead of %s

This makes the code a bit cleaner, specially for reading
_EMPEROR_FOOTER_HTML_STRING.
TST: Fix tests for layout changes
Merge pull request #258 from ElDeveloper/w3s

Resolve inconsistent layout problems