Heterogenous Map Keys trip the New Formatter

[hindol]

For example, the following map is aligned like this,

  {\I         1
   \V         5
   \X         10
   \L         50
   \C         100
   \D         500
   \M         1000
   [\I \V] 4
   [\I \X] 9}

[PEZ]

This needs to be fixed in cljfmt before we can do anything about it in Calva. Here's a PR to watch:

• align associative (Attempt to solve issue #36) weavejester/cljfmt#299