fixed desugaring of initializers

`stringVal ->> string ? = "aaa"`
is now desugared to
```
stringVal ->> string ?
[ some stringVal => stringVal = "aaa" ]
```
updated regressions for the initializers
Set the maximum string length for the Choco output to be either 16 or the length of the longest string constant, whichever is larger.
add lenses to IInt, IDouble and IString
fixed the bug whereby union of strings was getting concatinated
Release 0.3.6.1
Merge pull request #50 from gsdlab/develop

Release 0.3.6.1