search-mappings command

[supersaiyansubtlety]

based on #280

Adds a search-mappings command for searching a project's mappings using one or more regular expressions.

help entry:

- search-mappings
	Searches for class, method, field, and parameter names using regular expressions.
	Each can additionally be filtered using access expressions; methods, fields, and parameters can be filtered by type.
	An access expression is a boolean combination of access flag keywords. They support &, |, !, and parentheses.
	Available access flag keywords are public, private, protected, static, final, super, synchronized, open, transitive, volatile, bridge, static_phase, varargs, transient, native, interface, abstract, strict, synthetic, annotation, enum, mandated, module, record, and deprecated.

arg help:

Arguments:
Argument 0: [input-jar=]<path>
A path to the .jar file to use in executing the command.
Argument 1: [input-mappings=]<path>
A path to the file or folder to read mappings from.

Optional arguments:
Argument 2: [classes=]<regex>
A regular expression to filter class names.
Argument 3: [class-access=]<access-expression>
An access expression to filter classes.
Argument 4: [methods=]<regex>
A regular expression to filter method names.
Argument 5: [method-returns=]<regex>
A regular expression to filter method return type names. Pass 'void' to filter void methods.
Argument 6: [method-access=]<access-expression>
An access expression to filter methods.
Argument 7: [fields=]<regex>
A regular expression to filter field names.
Argument 8: [field-types=]<regex>
A regular expression to filter field type names.
Argument 9: [field-access=]<access-expression>
An access expression to filter fields.
Argument 10: [params=]<regex>
A regular expression to filter parameter names.
Argument 11: [param-types=]<regex>
A regular expression to filter parameter type names.
Argument 12: [param-access=]<access-expression>
An access expression to filter parameters.
Argument 13: [sort=]<NAME|PACKAGE|DEPTH>
How results should be sorted.
Argument 14: [limit=]<int>
A limit on the number of individual results to display per result type (class, method, field, parameter).
The total, unlimited result count is always reported.
A limit of 0 causes only counts to be reported and negative limits are ignored.

Also makes the LocalVariableDefEntrys of MethodEntrys' params obtainable and adds parameter indexing to EntryIndex.

Todo:

• rebase back onto Named command args #280 and target develop/2.7 once I get constructor params sorted
• support primitive and void types
• add option to limit result entries
• add access filter
• test
• javadoc

[supersaiyansubtlety]

I think this caching should be fine, but I want to bring attention to it just in case.

[supersaiyansubtlety]

rebased, ready for review