ProcessInput initial commit.  Handles a single command currently.
Debugging cleanup
Piped commands now working properly.
Remove trailing newlines from message payload.
Pass the error along when a command fails.
Run multiple commands in sequence instead of parallel.
run_interval 0 now continuously runs command on successful exit.
Refactor RunCmd for use outside of ProcessInput.
Set a default ticker interval for run_interval 0. 1 second.
ProcessInput initial commit.  Handles a single command currently.
Piped commands now working properly.
run_interval 0 now continuously runs command on successful exit.
Merge branch 'features/ProcessInput' of https://github.com/bzub/heka into features/ProcessInput
Merge branch 'features/ProcessInput' of https://github.com/bzub/heka into features/406-processinput
ignore vim swap files
refactored the subprocess execution into it's own module with tests
refactored the ProcessInput plugin to call out to the CommandChain
refactored where message packs are created and injected into the router
cleaned up plugin restart code
cleaned up configuration code to use an ordered list of structs for commands
removed calls to panic()
added documentation for ProcessInput plugin
added special case handling for io.EOF and "bad file descriptor" errors when reading from subprocess StdoutPipe()
updated process_chain test to not check the actual error message
string from stderr as it varies across platforms.
added missing punctuation from ProcessInput documentation
refactored out common parts of the ProcessInput tests