pidgin/nest

3f2e07a5be16
Install page: Show toc and add older versions link

Modified the install page so that it now shows:
- The table of contents at the beginning of the page. Had to modify the
markdown a bit to make this appear (it only shows it if there's no first level
heading in the md file).
- Added a new section to tell users where they can find the installers/binaries
for older versions of Pidgin/Finch.

Testing Done:
Ran `dev-server.sh` and verified content looked as intended

Reviewed at https://reviews.imfreedom.org/r/834/
{
"tabWidth": 4,
"useTabs": true,
"pluginSearchDirs": ["./"],
"proseWrap": "always",
"trailingComma": "es5",
"overrides": [
{
"files": "tools/**/*.js",
"options": {
"semi": false,
"singleQuote": true
}
},
{
"files": "package.json",
"options": {
"tabWidth": 2,
"useTabs": false
}
},
{
"files": "*.yaml",
"options": {
"tabWidth": 2
}
}
]
}