[BreakingChange] : Now TaskParameter keeps their object structure.

Change TaskParameter from String[] to hashtable.
This cause breaking change to use local variable in valentia  scriptblock.
Before : $args[0]
       : param($hoge); $hoge

after  : $args[0].Values
       : param($hoge); $hoge.Values
Merge pull request #64 from guitarrapc/TaskParameterKeepObjectStructure

[BreakingChange] : Now TaskParameter keeps their object structure.