provide implementation for plugin versioning #154
Merge pull request #155 from PDAL/issues/154-plugin-versioning

provide implementation for plugin versioning #154
Remove note about pdal.hpp from docs — DNE

I'm not sure if this documentation note should be replaced by something
else (another header that should always be included first).
Merge pull request #156 from gadomski/doc-fix

Remove note about pdal.hpp from docs — DNE
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.
Performance tests for chipper with & without cache

autzen-thin.las is probably too small to make a really good test, but
it's available in the source.
Avoid unnecessarily formatting in getDimension

For preformance, only format error messages if we're about to use them
in throwing an exception.
Merge pull request #158 from c42f/cjf-warnings-fix

Fix various compiler warnings and minor bugs
WIP optimizations to getDimension()

* Move name-based getDimension() implementation to getDimensionPtr,
  which returns a pointer rather than throwing exceptions, and also
  takes const char* strings to avoid additional allocation.

* Move las point dimension caching to use getDimensionPtr for efficiency

* Make do with a single lookups of multi_index container by name, by
  using equal_range early on.

* Fix potential bug in dimension inheritance by ensuring that we only
  iterate over the discovered equal_range, rather than potentially
  continuing to the end of the container.

TODO:

* UUID string parsing is BROKEN here - need a replacement for
  boost::uuids::string_generator which doesn't routinely throw.

* The API changes aren't well thought through here - getDimensionPtr()
  should probably replace getDimensionOptional()

* It's nasty having all those getDimension() variants - reduce them in
  number using boost::string_ref ?
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
Merge remote-tracking branch 'upstream/master' into getDimension_optimization
point at local FLANN so warnings are gone
remove ununsed ptr to environment, we can get this from the GlobalEnvironment anyway
getDimension perf tests + use string_ref for dimension names

* Convert C-style implementation of getDimensionPtr() to use
  boost::string_ref for clarity.

* Add performance test cases to exercise various usages of
  Schema::getDimension*().  These underscore the importance of avoiding
  exceptions here, which are roughly 100x as expensive as a dimension
  lookup.

* Included with performance tests is a helpful header from OpenImageIO
  for convenient high resoultion timing.
Remove duplicate lines from src/CMakeLists

The duplicate lines were in the OCI plugin code.
Merge pull request #161 from gadomski/remove-dup-cmake-code

Remove duplicate lines from src/CMakeLists