Handle external functions (add-ins).

Unfortunately we can't test this piece easily just yet.  Enabling add-in
functions would mess up the function list which is unit-tested and thus
fail if we enable add-ins in unit test.

Change-Id: Ieda5e5560d4c7e68d7c6272c5d85f2ac63bd4ee4
Fix indentation.

Change-Id: I260649aca445e03c52423d8f0a63eb4681d2a876
Handle matrix.

Change-Id: I084b2348b5c52151b0d0ea36d082ec2f2603e0d4
EncodeUrlMode always set to "by grammer". Remove it.

Change-Id: I7de308bbdaacc1fc60a142497acc2301c080e5dc
Try not to pass ScCompiler as a parameter.

Change-Id: I7ef58f0455f11a3eb2ac88ec76e9436fb48a74e2