Example versioning and vulnerability features

[ncerutti]

1. Example PR #1388

model_settings_vuln.json contains the following line:
"supported_oed_versions": ["1.5", "2.0"]

If the exposure data contains new codes incompatible with the latest compatible version of oed (2.0, in this case), these codes will be converted.

2. Example PR #1415

analysis_settings_vuln.json contains the following lines:
"vulnerability_settings": {
"replace_file": "vuln_adj.csv",
}

When loading the vulnerability data, data contained in the file vuln_adj.csv will be applied, replacing specific vulnerability functions.

3. Example PR #1426

analysis_settings_vuln.json contains the following lines:
"vulnerability_settings": {
"adjustments": {"2": 0.5 , "8": 1.5}
}

When calculating losses, the random numbers associated to vulnerability 2 will be multiplied by 0.5 (higher chance of falling into low damage bins) and those associated with vulnerability 8 will be multiplied by 1.5 (higher chance of falling into high damage bins).