Add licenses for XFree86 Inc. and some contributors including HP, SuSE and the FSF. Cleanup some stuff while here.

i119097: Update headers to Alv2 headers, this was supposed to be done earlier as for other sal os2 headers.

due to transition of extensions site to SF

also fixed some minor spelling and building instruction errors

Clean external licenses: Drop Sleepycat DB, some older MS runtime EULA, and a repeated Bitstream Vera License.