make Transaction a factory
let the transactions generate the number of currently available units and display that
fix transaction.numAvailable for converts, transfers, and exercises
a couple of small fixes around creating new securities and security names
Merge branch 'master' into split_fix

Conflicts:
	ownership/partials/cellDetails.html
only show "units available" on one side of 2-sided transactions (convert, exercise, etc)
have date affect the units available in the transaction details
format units available
fix conversion modal to display number of units available, and default to max available
spacing
automatically determine appropriate amount number of shares for exercises, forfeits and repurchases
show all lost units in addition to available units
Merge branch 'split_fix'
don't show share statistics if the transaction doesn't have units
Revert "convert transactions show correct units on both sides of the transaction" as it's no longer needed

This reverts commit 01198065a950cbb60783a81b877efe0e58cfbc15.

Conflicts:
	ownership/js/directives.js
Hiding action tab on unsaved grants. Fixes #535
put units and the unit stats above all other attributes in display mode
Fixing zombie on compose message icon
add summary of all units to each cell with units, and fix convertible debt conversion unit summary logic
better convert modal "shares available" functionality and styling