Add basic logging / performance logging structure

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Add basic logging / performance logging structure

    This commit adds dependencies in src/parent pom.xml for:
    - log4j v1.2.17
    - perf4j v0.9.16

    Dependencies are also added for the following child projects:
    - src/cli
    - src/core
    - src/geotools

    src/cli/src/main/java/org/geogit/cli/GeogitCLI.java was modified
    to pass existing geotools logging to log4j

    src/geotools/src/main/java/org/geogit/geotools/porcelain/ShpImport.java
    was modified to:
    - log which shapefile is being imported
    - log import time

    Log files are placed in ${user.home}/.geogit-log/{user, perf,
    stacktraces} allowing for the separation of user logs, development logs,
    and performance logs into different files for easier parsing of relevant
    information.