Create searchable index on string literals and integer literals

[pgoodman]

Basically, we should be able to do the eqivalent of Binary Ninja's or IDA Pro's "strings view," but for string literals from the program. Absent making a tool that will scan all StringLiteral expressions, this will require populating a full text searchable index at index time.

We should also have a similar index on integer literals. More care might need to be taken on how we go about the integer literal index.

[pgoodman]

This index could then be connected to token highlighting in the gui, so that all instances of a given integer value would be highlighted.