Micro-optimization

[Korijn]

Relates to #7

Changes:

• Avoids iterators (for loops) when it is unnecessary.
• Removed some redundant Pointer creation.
• Optimized the Pointer class, since it is used a lot.

Since patchdiff is typically used as a low level tool in hot codepaths, this kind of micro-optimization is worthwhile.

[berendkleinhaneveld]

Since you've added some extra benchmarks, it might make sense to use the same benchmarking strategy that I applied at observ where it runs the new benchmarks also on the code from master.

[Korijn]

Since you've added some extra benchmarks, it might make sense to use the same benchmarking strategy that I applied at observ where it runs the new benchmarks also on the code from master.

How's this?

[Korijn]

Pointer.evaluate got much faster which in turns helps the performance of apply and iapply.

Other changes led to marginal improvements.