Compiler can change position of start/end splash markers or even optimize-out
them completely, because they are not used in the fw.
Make them part of the splash data block, so their possition is always correct.
util/xbm2lbm was changed together with other c "images" to make it consitent.
These changes make it possible to compile open9x with old (avr-gcc 4.3.3,
avr-libc 1.6.7) and up-to-date (avr-gcc 4.6.2, avr-libc 1.8.0) build
environments. See Issue 1 for more details.