Many changes

- added sanitize using rnase-away
   - santize while PTC is running
- moved path of header file
- keep track of thermocycler time separate from pipette
- fixed bug in checking for 0 volume (use 0.01)
- don't move zero volumes
- added option finalconc arg to stage() to allow building master mixes
- added lihahome() to move liha to home instead of using extra washes
- keep track of removals of liquid from samples
- added Sample.clearall() to restore sample to init time values
Updated elapsed time constants based on parselog output
Added more wash options
Added delayed dispenses

Collects up dispenses so that movements are more efficient
Output elapsed time for each command type

Use for tracking elapsed time estimates in worklist.py