Minor refactoring

Trivial update

Fixes sqlmapproject#4728

Version bump related to the merged pulls

Fixes sqlmapproject#4664

Fixes sqlmapproject#4625

Speedup of caching for char encoding (non-Unicode chars in page)

Fixing HTTP chunking for Python2.6

Version bump (1.5)

Patch for known NCHAR/UNION-query SQLi problems