Strain template updates

[Gonza10V]

• Remove non used SO terms

• Change column definition to be A to B for ontology terms

• Clean unique names

• Change plasmid column to be Plasmid 1 (drop down), Plasmid 2 (drop down), extra plasmids (free text).

[Gonza10V]

@cjmyers please check https://github.com/SynBioDex/Excel-to-SBOL/blob/master/resources/templates/Strains.xlsm
and close the issue if you area happy with the features implemented

[cjmyers]

Looks good, but the More Plasmids column is not allowing me to enter comma separated list of ids.

[Gonza10V]

now more plasmids is free text
one minor thing is that we need to release a new version of the package to change the name of the welcome page.
added as issue #174