blocks: fixed use of "not" for "!".
README files: Fix typos.
README: Fix incorrect URL.
cmake: fixed boost version test

"if(${Boost_VERSION} EQUAL ${ver})" fixed

if §{Boost_VERSION} is unset, the expression expands to something like
if( EQUAL "104601" )
which generates a parser error. Since it's a string comparison, anyway,
I replaced it by the specific
if("${Boost_VERSION}" STREQUAL ${ver})

fed
Merge remote-tracking branch 'uwehermann/readme_fixes' into maint
runtime: corrected spelling
digital: fix false trigger bug in correlate_access_code_tag, add QA code.
grc: fix xterm setting check
grc: catch EOFError on fg exit
Merge remote-tracking branch 'gnuradio-wg-grc/maint_grcwg' into maint
Merge remote-tracking branch 'bistromath/pkt' into maint
grc: On Linux, respect x-terminal-emulator
grc: fix port type cache for empty types