Variable not being substituted in cell magic with $ or {}

[cab938]

Sometimes the same query passed to the line magic, %sql, won't work in the cell magic, %%sql, specifically when using a variable substitution with a dollar sign $.

MWE show below using publicly available dataset. Tested with ipython-sql 0.4.0

This similarly fails with the {} notation:

[duncandewhurst]

Looks like the same issue I reported in #177