[DOC] update history

HISTORY.md

@@ -1,3 +1,20 @@
+##0.7.38
+
++ Improvements to multi-server support. Fixed an issue where a server's score was not reset and connections would keep dropping after being connected for a significant amount of time.
+
++ Improvements in order book support. Added support for currency pairs with interest bearing currencies. You can request an order book with hex, ISO code or full name for the currency.
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++ Fix value parsing for amount/currency order pairs, e.g. `Amount.from_human("XAU 12345.6789")`
+
++ Improved Amount parsing from human readable string given a hex currency, e.g. `Amount.from_human("10 015841551A748AD2C1F76FF6ECB0CCCD00000000")`
+
++ Improvements to username normalization in the vault client
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++ Add 2-factor authentication support for vault client
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++ Removed vestiges of Grunt, switched to Gulp
+
+
 ##0.7.37
 
 + **Deprecations**