Merge remote-tracking branch 'upstream/master' into develop

Conflicts:
    core/pom.xml
    core/src/main/java/com/google/monacoin/core/NetworkParameters.java
    core/src/main/java/com/google/monacoin/params/MainNetParams.java
    core/src/main/java/com/google/monacoin/wallet/DefaultCoinSelector.java
    core/src/main/java/com/google/monacoin/wallet/DefaultRiskAnalysis.java
    core/src/test/java/com/google/monacoin/core/PeerGroupTest.java
    core/src/test/java/com/google/monacoin/core/TestWithPeerGroup.java
    core/src/test/java/com/google/monacoin/core/WalletTest.java
    core/src/test/java/com/google/monacoin/wallet/DefaultCoinSelectorTest.java
    core/src/test/java/com/google/monacoin/wallet/DefaultRiskAnalysisTest.java
    examples/pom.xml
    pom.xml
    tools/pom.xml
    tools/src/main/java/com/google/monacoin/tools/WalletTool.java
rename folder s/dogecoin/monacoin/
s/dogecoin/monacoin/
change key
revert getMinNonDustValue
Tweaks to fee calculation
Go back to java 6 for tools.
Fix to accept monacoin peers
Remove comments
Implement Kimoto Gravity Well