Enable Compound Tag Selection and Removal to work with atomic tags and strings

Enable Compound Tag Selection and Removal to work with atomic tags, strings, and compound tags interchangably.

Adds pred_fn to remove_by_tag and excluding_by_tag methods. To enable control of any/all predicate used.
Changes TagSet to exclude compound tags from result (this enables select/remove by tag to work by converting the input argument to a TagSet which normalizes the values to the same set of atomic tags)
- before: TagSet([Tags.ITEM_ID]) # => {Tags.ID, Tags.ITEM_ID, Tags.ITEM}
- after: TagSet([Tags.ITEM_ID]) # => {Tags.ID, Tags.ITEM}
Updates TagSet to parse string values corresponding to existing tags with any string casing (currently only matches a tag if it is in lowercase, e.g. "item")
- before: TagSet(["ITEM"]) # => {"ITEM"}
- after: TagSet(["ITEM"]) # => {Tags.ITEM}

Selection with Compound Tag

Selecting from a schema with ITEM and ID tags is currently not working when passed a compound Tag Tags.ITEM_ID or

(
    Schema([ColumnSchema("item_id", tags=[Tags.ITEM, Tags.ID])])
    .select_by_tag(Tags.ITEM_ID)
)
# => []

(
    Schema([ColumnSchema("item_id", tags=[Tags.ITEM, Tags.ID])])
    .select_by_tag(Tags.ITEM_ID)
)
# => [ColumnSchema("item_id", ...)]

(
    Schema([ColumnSchema("item_id", tags=[Tags.ITEM, Tags.ID])])
    .remove_by_tag(Tags.ITEM_ID)
)
# => [ColumnSchema("item_id", ...)]

(
    Schema([ColumnSchema("item_id", tags=[Tags.ITEM, Tags.ID])])
    .remove_by_tag(Tags.ITEM_ID)
)
# => []