validate color palette channel index in opj_jp2_apply_pclr (fixes 451.pdf.SIGSEGV.f4c.3723)

TODO: there might be a better place to validate this number, however AFAICT in opj_jp2_read_cmap the number of image components isn't available yet
validate tile sizes in opj_j2k_read_siz (fixes at least 2539.pdf.SIGFPE.706.1712, 3622.pdf.SIGFPE.706.2916 and 4008.pdf.SIGFPE.706.3345)

BTW: this issue has originally been reported upstream as http://code.google.com/p/openjpeg/issues/detail?id=169
replace assert with reference to testcases
validate component indices in opj_jp2_apply_cdef (fixes 4149.pdf.SIGSEGV.cf7.3501)
Merge branch 'fixes' into sumatrapdf