Added validators getters for vectors.

Started Implementation of Waterfall step helper Widget
Relates to #168
Implemented Widget for waterfall

Needs Triggers Editor
Relates to #168
Working on trigger editor.

Relates to #168
Added trigger structure editor

Few Fixes in InfixToPostfix
Relates to #159
Widget for waterfall almost complete, needs implementation on VBA sub for output and detection of input from interest or principal waterfall

Relates to #168
Implemented widget for waterfall

Relates to #168
Implemented size multiplier for tranche trigger
Fixed operators * and / for bloomberg vectors
Widgets implemented but now a Diff in calculations is triggered and needs to be solved

Relates to #168
If there are unallocated funds at the end of the waterfall they are added to excess spread
Almost finished implementing widgets to edit triggers and the waterfall.

Need to hide waterfall steps that make no sens in the current waterfall (e.g. Reinvest principal in interest waterfall)
Relates to #168
Implemented input of Triggers and Trigger Structures in waterfall

Closes #168
Merge branch 'Development'