Added power law fit using LSE and WLSE:

LSE: very simple code -> one equation per pixel
WLSE: based on MLE -> weights are optimized iterative
Changed line endings:

Eclipse uses CRLF, but the repository uses LF.
Merge pull request #8 from EFTEMj/add_WLSE&LSE_to_elemental_map

Add wlse&lse to elemental map