adding Apache 2.0 LICENSE file to root of project

Same as in the individual files, just a bit easier to tell this
code is licensed now.
Merge pull request #88 from sghill/add-license-file

adding Apache 2.0 LICENSE file to root of project
Fixing aspectj maven plugin configuration so that test dependencies are not pulled in at compile-time
#85 Replaced org.apache.commons.lang3.Validate with
com.google.common.base.Preconditions. Removed Apache Commons-Lang
dependency and migrated some necessary classes. HashCodeBuilder and
EqualsBuilder have been migrated also, as they cannot be replaced by
com.google.common.base.Objects.equal/hashcode.
Merge branch 'ApacheCommonsDependencyRemoval' of github.com:roberttaylor426/RoboBinding into ApacheCommonsDependencyRemoval