models:

Added missing logic tree attributes to HazardCurveModel.

Also corrected the attribute `quantile` to `quantile_value`.
models:

Added HazardCurveData and Location container classes.
These are used by the hazard curve xml parser.
hazard/parsers:

Corrected `quantile` to `quantile_value`.
hazard/parsers:

Corrected hazard curve parser to extract logic tree metadata as well.

Before, it was only designed to work with statistical results.
hazard/parsers:

Updated the interface of the objects yielded by the hazard curve parser
to match that of the hazard curve writer.
tests/hazard/parsers_test:

All tests pass.
tests/data:

Added some hazard curve test files.
hazard/parsers:

Hazard curve parser stores metadata in an OrderedDict, consistent with
the hazard curve writer. This makes data handling stable and consistent.
tests/hazard/parsers_test:

Added a test case to chain a hazard curve parser and writer together.
The XML produced should be the same as the input.
Merge pull request #97 from larsbutler/fix-hazard-parser-lts

Hazard curve parser updates/corrections

[r=micheles] [f=*trivial]