NF: class visual.InstructionScreen

goal = simplify code in coder demos
design pattern = display text, wait for any key, quit on escape
RF: a couple code simplifications, esp rating scale demo
RF: better visual.InstructionScreen

simpler, and kwargs can now control the format of the TextStim
RF: add InstructionScreen() .show() method

- allows separation of instr object creation from its display / use
FF: Fix NameError when using keyboard component

After recent changes it was not possible to use the keyboard component
because opening the property dialog raised a NameError. This was fixed
by using an available Sizer.
FF: Fix parameter being in wrong tab in settings

In Builder's experiment settings the optional parameter for window size
was displayed in the "Basic" tab and not the "Screen" tab where related
check box is located. This was fixed by changing category to "Screen".
ENH: Corrected comment in builder source
ENH: Comment debug print in builder source
Merge pull request #460 from philippwiesemann/fix-builder-settings-category

FF: Fix parameter being in wrong tab in settings
Merge pull request #459 from philippwiesemann/fix-builder-keyboard-crash

FF: Fix NameError when using keyboard component
ENH: builder components now using tabs for (optional) param categories
BF: movie autodraw
ENH: only setNameColor (for extended code params) if name exists
NF: added psychopy.data.checkValidFilePath() replaces code in builder scripts

This wasn't just added for kicks - it was needed to make it possible
to add customised file names for experiments. If they're custom then
they need to check the compile the folder name later so we need a
better way to check the path is valid
NF: custom data filenames are now possible from Builder experiment settings
FF: fix to new system for settings loop controls (was failing on type switch)
FF: Component Name validator working again after addition of param categ tabs

Apparently child panels need to be explicitly validated as well as the
parent.

I also removed some old debug lines and several lines of old, commented-out
code
DOC: fORP when using USB
DOC (?): use "default text" as default text; closes #462

previously was "nonsense"
REVERT remove visual.InstructionScreen