pom: change scopes from provided to compile: commons-lang3, mongo-java-driver, spring-beans

Otherwise, if used in a project that doesn't otherwise, have said dependencies, ClassNotFoundExceptions will occur.

An example from my Grails project:

    org.apache.commons.lang3.time.DateFormatUtils. Stacktrace follows:
    Message: org.apache.commons.lang3.time.DateFormatUtils
        Line | Method
    ->>  156 | findClass    in org.codehaus.groovy.tools.RootLoader
    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    |    424 | loadClass    in java.lang.ClassLoader
    |    128 | loadClass .  in org.codehaus.groovy.tools.RootLoader
    |    357 | loadClass    in java.lang.ClassLoader
    |    133 | logChangeSet in org.mongeez.dao.MongeezDao
    |     54 | execute      in org.mongeez.ChangeSetExecutor
    |     42 | execute . .  in     ''
    |     40 | process      in org.mongeez.Mongeez
    |     58 | execute . .  in org.mongeez.MongeezRunner
    |     40 | run          in grails.mongeez.MongeezController
    |   1145 | runWorker .  in java.util.concurrent.ThreadPoolExecutor
    |    615 | run          in java.util.concurrent.ThreadPoolExecutor$Worker
    ^    724 | run . . . .  in java.lang.Thread