[mkgmap-dev] Commit: r2976: Fix BitReader.sget2() in the multi word cases.

Version mkgmap-r2976 was committed by steve on Sat, 18 Jan 2014 Fix BitReader.sget2() in the multi word cases. The final byte determines if the result is positive or negative and the number of special words beforehand make that result bigger. This only affects reading non-mkgmap files. Added a couple of tests for them.