This fixes two regressions, caused by #1167 and #1191 .

No matter what LANGUAGE_CHOICE was set to it would always take the en branch.
I revamped it a bit to use a macro to create the language include file name. This required a slight tweak to the RU declaration since it's special-cased in a couple places in code.

This is an attempt to pull my changes from #1222 over.

Breaking up languages.h makes it easier to translate. Using language
codes makes it easier to select a language and sets the naming standard.

Here comes a compile-time operation to match the extruder symbols on the
info screen to the set number of extruders in configuration.h.
When only one extruder is selected, the "1" on the symbol will not be
displayed.

Added support to show the filament width on the status line of the
graphic LCD.  The status will show for 5 sec and then switch over to
data.  Status can be seen by clicking the button.

#elsif does not exist #elif is correct

Diffed and merged, preserving my updates

- fixed long menu entries (>14 or >18 chars) caused overrun in dogm lcd
implementation
- fixed pin set problem when in interrupt
- much faster ST7920 SW-SPI implementation
- increased ST7920 framebuffer size for more speed

Reviert previous change of #if BLAH_PIN > 0 to #if defined(BLAH_PIN) &&
BLAH_PIN > -1. Unfortunately some times pin 0 is used. For my sins I've
gone through and replaced all unsafe checks of #if BLAH_PIN > -1 with
the safe version.

This contains the menues, status screen etc...