BUG: dictionary entries not being properly merged/overwritten (closes #418)

applications/test/dictionary/testSubkeyword

src/OpenFOAM/db/dictionary/dictionary.C

src/OpenFOAM/db/dictionary/dictionary.H

src/OpenFOAM/db/dictionary/dictionaryIO.C

src/OpenFOAM/db/dictionary/entry/entryIO.C

...ictionary/functionEntries/inputModeEntry/inputModeEntry.C

...ictionary/functionEntries/inputModeEntry/inputModeEntry.H

...M/db/dictionary/functionEntries/removeEntry/removeEntry.H

src/OpenFOAM/db/dictionary/primitiveEntry/primitiveEntryIO.C