Runs make clean before installing an extension.
Merge pull request #425 from shinnya/feature/extension/make_clean

Runs make clean before installing an extension.
Using tr command to instead of bourne shell IFS function. fixes #431

Signed-off-by: Rack Lin <racklin@gmail.com>
Merge pull request #432 from racklin/bugfix/431

Using tr command to instead of bourne shell IFS function.
Merge remote-tracking branch 'origin/develop'