Simplify the interface to the symbol table, saving 600 bytes of code space.
Enhance the spellfix extension with the ability to specify a rowid when
inserting new rows.
Change a while-loop into a do-loop in sqlite3VdbeSerialPut() for a small
size reduction and performance improvement.
Get the sqlite3VdbeSerialGet() routine to run faster by avoiding the use
of local variables.
Handle the 4-byte integer case in the stackless routine.
Improve the performance and reduce the size of the sqlite3VdbeSerialGet()
routine by avoiding the use of stack.
Performance improvement in the printf() logic by avoiding unnecessary stack
pointer movement.
Split the sqlite3Error() routine into sqlite3Error() and
sqlite3ErrorWithMsg(), for a slight size reduction and performance increase.
Performance enhancement in sqlite3PutVarint().
Combine the pcacheAddToDirtyList() and pcacheRemoveFromDirtyList() routines
into a single pcacheManageDirtyList() routine.  The resulting binary code is
slightly faster and a few bytes smaller.
Performance enhancements in the b-tree mutex logic.
Factor the saveAllCursors() routine of btree.c into two separate routines,
for a noticable performance improvement.
Another performance tweak: Split the sqlite3BtreeCursorHasMoved() routine 
into two with the second routine named sqlite3BtreeCursorRestore().  The first
now only reports whether or not the cursor has moved and the second tries to
restore the cursor.  This allows the sqlite3VdbeCursorMoveto() routine to be
refactored to avoid stack pointer movements, for a noticable performance gain.
Performance optimization in the applyAffinity() logic inside the VDBE.
Improved performance in the type handling of arithmetic operators in the VDBE.
Make the implementation of the sqlite3_aggregate_context() interface faster
for second an subsequent invocations.  This helps all aggregate functions to
perform better.
Changes to sqlite3ScratchMalloc() that make the entire memory allocation
interface a little faster and about 100 bytes smaller.
Fix a variable-declaration after code problem in btree.c.  Harmless in
GCC and CLANG but unacceptable for MSVC.
Another memory allocator performance optimization.
Faster implementation of the sqlite3ApiExit() routine.