Write out generic metadata in XLIFF as context-group/context data rather than custom okp:meta

[Chase Tingley]

See discussion here: https://groups.google.com/d/msg/okapi-devel/JrqU4gXHysQ/TZ38Yy7jBAAJ

The proposed solution is to replace:

<okp:meta type=”key1”>value1</okp:meta>
<okp:meta type=”key2”>value2</okp:meta>

‌

with

‌

<context-group>
<context context-type=”key1”>value1</context>
<context context-type=”key2”>value2</context>
</context-group>

‌

[Chase Tingley]

Fixed in PR 364.