(portage-#9) Add portage environment facts

This adds a set of facts for the variables outputted by `emerge --info`.
It downcases the variable names and prefixes "emerge_" to each fact to
avoid ambiguity.
(portage-#9) Allow numbers in emerge fact names

APACHE2_MODULES is a valid variable name but the APACHE2 was being
stripped out. This resolves that issue.
(portage-#23) Deduplicate package use flag change exec

The exec resource used to rebuild portage packages on changed use flags
was not unique across resources and could cause a duplicate resource
error. This commit adds the portage::package name to the title to avoid
this and ensure uniqueness of the command.
Merge branch 'issue_9-emerge-info-facts'
Merge branch 'issue_23-duplicate-exec'
Update CHANGELOG and Modulefile for 1.1.0