Added tandem-converter GUI and decoupled from hipsr_core

Added GUI for stitching together HIPSR and MBCORR files. Along with this I've removed the hipsr_core dependency and switched to including files in lib/. The idea is to make hipsr_reduction easier to install for end users, and to stop changes to hipsr_core affecting hipsr_reduction.

Signed-off-by: Danny Price <dan@thetelegraphic.com>
Housekeeping commit

Removing tandem/ directory from repo, and added gitignore rules

Signed-off-by: Danny Price <dan@thetelegraphic.com>