Update gosrc data.

Add Go program to generate the data used by the package. Add go:generate
comment to invoke the program.

Update the data to Go 1.4 and the latest TLDs.
Upgrade to Bootstrap v3.3.1 and use a CDN
Merge pull request #211 from jayschwa/bootstrap-v3.3.1

Upgrade to Bootstrap v3.3.1
Enable source line links for googlesource.
Merge pull request #210 from garyburd/gosrcdata

Update gosrc data.
Get standard packages from golang.org.

Scrape golang.org to get source files for standard packages. Link
standard package documentation to the source files on golang.org.

Update to handle the new Go 1.4 directory structure with a fallback to
the Go 1.3 directory structure.
Merge pull request #213 from garyburd/googlesourcelinefmt

Enable source line links for googlesource.
Merge pull request #216 from garyburd/ghmove

Get standard packages from golang.org.
Link to source using go-source meta tag.

The go-source meta tag is similar to the go-import meta tag used for vanity
package paths. The structure of the tag is:

    <meta name="go-source" content="prefix home directory file">

The prefix field is the import path corresponding to the repository root.

The home field is the URL of the repository's home page.

The directory field is a URL template for a page listing the files in the
package. The following substitutions are made in the directory template:

    {dir} - The import path with prefix and leading "/" trimmed.
    {/dir} - If {dir} is not the empty string, then {/dir} is replaced by "/" +
             {dir}. Otherwise, {/dir} is replaced with the empty string.

The file field is a URL template for a link to a line in a source file. The
following substitutions are made in the file template:

    {file} - The name of the file
    {line} - The decimal line number.

The server currently handles the case where {file} comes before the fragment
delimiter (if any) and {line} comes after the fragment delimiter.

The meta tag content attribute must contain four fields. Use "_" to fallback to
gddo's defaults for home, directory and file.

To improve the readability and maintainability of the code, change parseMeta()
return structs instead of a map[string]string. Also, move some of the
validation logic in parseMeta() to getDynamic().

Add tests for getDynamic().

See https://github.com/niemeyer/gopkg/pull/31 for the corresponding
change to gopkg.in.