#2 changes for mzML 1.1

[Matt Chambers]

This will entail quite a few changes:
- find every spectrum-level param in readers and writers and move it to the description (spectrum type, ms level)
- add defaultDataProcessingRef to SpectrumList and ChromatogramList
- move softwareRef from DataProcessing to ProcessingMethod
- check all usage of the MS_m_z term (it should only be used as a unit now); use MS_selected_m_z in SelectedIon
- change isolation window encoding from m/z and width to upper and lower bounds
- eliminate redundant spectrum type / scanning method cases
- move existing Scan parameters to Acquisition
- move ScanWindowList to Acquisition
- remove Scan type entirely
- reduce SoftwareParam to a normal cvParam; move version attribute to Software type