Fixes #1275. Fixes pom dynamic revision conversion

Fixes #1275

Ivy and pom uses slightly different notation for version range and dynamic revision. This change fixes the dynamic revisions involving “+”.

First, when a revision like “1.1+” is found, it will now be treated as “1.+”.
Next, when it finds a revision like “1+” is found, it will be treated as “+”. The conversion of “+” is hardcoded to be “[0,)”.

- http://ant.apache.org/ivy/history/2.3.0/ivyfile/dependency.html
- http://maven.apache.org/enforcer/enforcer-rules/versionRanges.html

/review @havocp 
this will accept `total gobbledygook blaah blashdflh sdfh sdlj 4;l5kj423;lk5j4123;kj +` right? I guess versions can have alpha chars so we just have to live with that? Or is there some kind of other filtering going on before we get here