Adding all the changes from the develop branch#3

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manikey123 merged 12 commits intomanikey123:782_test_p1from bitshares:develop

Jan 15, 2019

+68-32

Commits on Dec 27, 2018

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Commits on Jan 1, 2019

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Commits on Jan 4, 2019

removed boost signals (no longer used)
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Commits on Jan 6, 2019

Merge pull request #1514 from bitshares/jmj_1512
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Commits on Jan 7, 2019

Commits on Jan 8, 2019

Make sure price_to_string works and throws as it should
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Commits on Jan 11, 2019

Separate throws from edge cases that should work
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