Create function that converts .ntt to four .ncs files

[mvdm]

Should do something like:

• Initialize tvec, sampled at 32 kHz, with four rows of data initialized to zeros
• For each spike in the .ntt file, paste the waveforms into the data at the correct time
• (maybe check for overlaps... how best to handle?)

[ecarmichael]

This is almost completed for synthetic data as of the beginning of the Dartmouth Brain Hack.

• convert ntt into 4 csc files with zeros between spikes

• added an overlap checker.

• write back to .ncs file

• use and test real data.