docs: Fix a few typos

There are small typos in:
- dataset/table.py
- docs/queries.rst
- docs/quickstart.rst

Fixes:
- Should read `significant` rather than `signficant`.
- Should read `parameterisation` rather than `paramterisation`.
- Should read `explicitly` rather than `explicetly`.

Signed-off-by: Tim Gates <tim.gates@iress.com>

dataset/table.py

@@ -717,7 +717,7 @@ class Table(object):
     def __iter__(self):
         """Return all rows of the table as simple dictionaries.
 
-        Allows for iterating over all rows in the table without explicetly
+        Allows for iterating over all rows in the table without explicitly
         calling :py:meth:`find() <dataset.Table.find>`.
         ::