Merge pull request #17 from aseering/master

shell_load_package -- UDL shell extension
move heatmap project from internal repo to external repo
Added 3 allowable input data types for heatmap, added weighted points
Updated README use info and parameters for heat_map()
Removed out of date text
Changed parameter name flip_x to xflip for consistency.
Updated README with correct options for image function
Merge branch 'master' of github.com:veilrap/Vertica-Extension-Packages
Merge pull request #18 from veilrap/master

HeatMap update
Adding the avro parser udx into github
Merge pull request #19 from ramcn/master

avro parser added
The Email UDX
Merge pull request #20 from awleblang/master

Email UDX
make build directory if it doesn't exist and fix comments to SQL
Check exit code of shell command
Proper output of exit status
Merge pull request #22 from jakajancar/shell_load_error_checking

Check exit code of shell -- Thanks Jakajancar
Major refactoring
Using ostringstream for building env vars, and renamed SPLIT vars
Split ProcessLaunchingPlugin and popen3 into header and source files