Make TransformInput() a non-member function.

Change-Id: Ieb077b6ce661e2885d6010519f137235a048f9df
Protect those global symbols containers with mutex during initialization.

Change-Id: Id15b3e1a2bfebd2ea795fd412a259f125f5d9bab
Allow non-pooled instance of SvNumberFormatter inside ScCompiler.

Change-Id: I645079254621c2f2684a69116b094e37e46f46f4
Allow instantiation of more than one SvNumberFormatter from the document.

Change-Id: Ide6875e031268337bf6a21286176a38905c12691
Perform formula cell compilations in multiple threads during xlsx import.

One sheet per thread. Right now the thread count is set to 1 due to non
re-entrancy of a large portion of Calc core, and beyond. We need to fix
that first before setting the thread count to more than 1.

Change-Id: I6997c1e9540de939f1f00b1798e2b32059787ae5