Adds More Server-Side Filtering Options for sl cci list.

Examples:
    sl cci list --datacenter=dal05
    sl cci list --network=100 --cpu=2
    sl cci list --memory='>= 2048'
    sl cci list --tags=production,db

* CLI: Moves NestedDict to top-level utils module so the managers can use it.
* CLI: Adds to_dict() method to NestedDict since the XML-RPC library is too strict about types.
Removes private filtering option
Moves query_filter() to SoftLayer.utils
Adds more documentation about filters

* Adds 'filters' module so that 'sl help filters' will output help text
  about how to use filters
* adds reference to 'sl help filters' in 'sl cci list' help text.
* makes filters easier to use. The space is not required in between the
  operation and the query value. For example '>2' will work as a filter.
Polishes filters Help Text

* Adds details for whether or not the filter is case sensitive or not.
* Reorders operation list/examples
* Adds ~ operator which is a case sensitive match.
Merge pull request #73 from sudorandom/filtering

Adds More Server-Side Filtering Options for CCI listing.