Grammar: Support ON INSERT in foreign key clauses

Allow ON INSERT in foreign key clauses like this:
CREATE TABLE x
(
	y INTEGER REFERENCES ref(id) ON INSERT CASCADE
)
Note that ON INSERT is allowed by SQLite but missing in the SQLite
documentation.

This partially fixes EoD's problem in issue #63.
Grammar: Fix multiple primary keys with conflict clause

Fix handling of multiple primary keys followed by a conflict clause like
in thix table definition:
CREATE TABLE [explore_records]
(
	[system_id] INTEGER NOT NULL REFERENCES [star_systems](id),
	[player_id] INTEGER NOT NULL REFERENCES [players](id),
	PRIMARY KEY ([player_id], [system_id]) ON CONFLICT ABORT
)

This partially fixes EoD's problem in issue #63.
Grammar: Allow multiple table keys which are not separated by commas

Fix table definitions like this...
CREATE TABLE [player_tech_branches]
(
	[from_id] INTEGER NOT NULL REFERENCES [techs](id),
	[to_id] INTEGER NOT NULL REFERENCES [techs](id),

	UNIQUE ([from_id], [to_id]) PRIMARY KEY ([from_id], [to_id])
)
...where there are multiple keys which are not separated by commas.

This partially fixed EoD's database in issue #63.
Remove \r characters from table definitions while reading DB layout

Remove all \r characters from a table defintion when reading it. This
makes sure it doesn't appear as a invalid character in the UI.

This commit improves the displaying of EoD's database from issue #63.