Introduced lcd_strlen() and lcd_strlen_P().
Replaced the old functions where necessary.
Reworked language_ru.h.
Speeded up test for zero length string in cardreader.cpp
* Depending on extruder count, will add menu items for ultralcd to edit
individual PID parameters for each extruder
* Added menu items to each language_xx.h
* Builds OK, but recommend testing with typical LCD
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.
