Optimisations

[MiahNelah]

I notice there is a lot of room to optimize this module:

• I rework all compendiums indexes calls to reduce them and exploiting latest api
• I rework random spell scroll generation to avoid loop and indexes calls as much as possible

Result is a good improvement in roll table performance on big tables with multiple draws.

[ultrakorne]

I notice there is a lot of room to optimize this module:

• I rework all compendiums indexes calls to reduce them and exploiting latest api
• I rework random spell scroll generation to avoid loop and indexes calls as much as possible

Result is a good improvement in roll table performance on big tables with multiple draws.

@Daimakaicho I merged the other pr first, was the other one older?

[MiahNelah]

I did #93 first, but merging would have been easier by merging this one first. On this conflict, ignore createTableFromCompendium() method from this pr.