only use PUBLIC in PDAL_LINKAGE if CMake supports it, otherwise stick with LINK_PUBLIC
Merge branch 'master' into issues/264-pdal-linkage
Very simple decompression for BPF.
Add a sbet reader

Sbet is a simple binary format used to store inertial measurement unit
(IMU) data. These data include position and trajectory information.
Simplify some code in dimension.
Make things fit in 80 columns.
Merge pull request #293 from abellgithub/bpf

Very simple decompression for BPF.
turn off clang builds for now
Merge pull request #295 from abellgithub/dimension

Simplify some code in dimension.
Merge pull request #294 from gadomski/sbet-reader

Add a sbet reader
Merge pull request #297 from PDAL/issues/264-pdal-linkage

Use PUBLIC linkage only if CMake > 2.8.12, otherwise use LINK_PUBLIC