Fix minor memory leak of stage factory
Fix various compiler warnings

* Mark boost and python headers as system headers to avoid a pile of
  (mostly boost) warnings in headers we don't control.

* Remove assertion about the return value of memcpy, because memcpy
  unconditionally returns the dest buffer regardless of success.

* Avoid unused variable warnings
  - When building without hexer
  - Due to variables only used in asserts
  - Unused endianess variable

* Fix bug in las writer when reading uint8_t intensity from buffer,
  which would have accessed a bogus pointer and caused a segfault.
Merge pull request #158 from c42f/cjf-warnings-fix

Fix various compiler warnings and minor bugs
increment boost to 1.54, add asio, string_ref, and regex
update script for bcp'ing 1.54
compile new additions for 1.54
Merge pull request #160 from PDAL/issues/160-upgrade-boost-154

Upgrade boost to 1.54
point at local FLANN so warnings are gone
remove ununsed ptr to environment, we can get this from the GlobalEnvironment anyway