Begin removing dependencies on Guava

[sjamesr]

I wrote all this before Java 8 was a thing, we can probably remove Guava as a dependency now. This will make distributing and using jfreesane easier.

[coveralls]

Pull Request Test Coverage Report for Build 352

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 112 unchanged lines in 12 files lost coverage.
• Overall coverage increased (+1.5%) to 81.51%

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Files with Coverage Reduction	New Missed Lines	%
/home/travis/build/sjamesr/jfreesane/src/main/java/au/com/southsky/jfreesane/SaneParameters.java	1	94.12%
/home/travis/build/sjamesr/jfreesane/src/main/java/au/com/southsky/jfreesane/SaneEnums.java	2	88.89%
/home/travis/build/sjamesr/jfreesane/src/main/java/au/com/southsky/jfreesane/OptionGroup.java	3	63.64%
/home/travis/build/sjamesr/jfreesane/src/main/java/au/com/southsky/jfreesane/SaneWord.java	4	82.76%
/home/travis/build/sjamesr/jfreesane/src/main/java/au/com/southsky/jfreesane/FrameReader.java	6	84.31%
/home/travis/build/sjamesr/jfreesane/src/main/java/au/com/southsky/jfreesane/SanePasswordEncoder.java	6	6.67%
/home/travis/build/sjamesr/jfreesane/src/main/java/au/com/southsky/jfreesane/SaneDevice.java	7	85.71%
/home/travis/build/sjamesr/jfreesane/src/main/java/au/com/southsky/jfreesane/RateLimitingScanListeners.java	9	0.0%
/home/travis/build/sjamesr/jfreesane/src/main/java/au/com/southsky/jfreesane/SaneSession.java	9	79.86%
/home/travis/build/sjamesr/jfreesane/src/main/java/au/com/southsky/jfreesane/SaneImage.java	12	84.62%
<!--	Total:	112		-->

Totals
Change from base Build 316:	1.5%
Covered Lines:	939
Relevant Lines:	1152

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💛 - Coveralls