lcdhw: SQM4_EB LCD support added. The driver is derived from the K70 LCDC module.
Bugfix #2: D4D_FileIsAbsolutePath fails for general drive identifiers.

Simple check of the second character of given string was replaced
by a check of first D4D_DRIVE_MAX_STRLEN characters.
Argument validity check added, too.
Merge pull request #5 from ymanCZ/sqm4

SQM4 edits
I checked the code and I think this will be good improvement for eGUI. Thanks