Documents two-variable for loop with sequences.
Adds some documentation related to exceptions.
Fixes rst format for enumerated list in html output.
Renames each proc to map, each is left deprecated.
Moves addr out of tutorial into manual, indexing it too.
Adds randomize(seed) for repeatable pseudo random numbers.

Also fixes srand48() type to clong.
Merge pull request #312 from gradha/pr_adds_some_docs_about_exceptions

Adds some documentation related to exceptions.
Merge pull request #315 from gradha/pr_adds_example_of_addr_cast_usage

Adds example of addr/cast usage and indexes addr.
Merge pull request #313 from gradha/pr_fixes_rst_format_enumerated_list

Fixes rst format for enumerated list in html output.
Merge pull request #311 from gradha/pr_documents_two_variable_for_loop

Documents two-variable for loop with sequences.
Merge pull request #316 from gradha/pr_renames_each_to_map

Renames each proc to map, each is left deprecated.
Merge pull request #306 from gradha/pr_adds_randomize_with_specific_seed

Adds randomize(seed) for repeatable pseudo random numbers.