Skin pregeneration missing agent versions

In cases where skins specify overlapping version ranges, skin pregeneration may fail to generate certain style sheets.

For example, imagine the skin specifies @agent rules for the following version ranges:

1. min-version:1
2. max:version:3
3. min-version:8

With our current implementation, we only attempt to generate style sheets for the start and end of each version range.

For the above example, this would be:

• 0 (start of #2)
• 1 (start of #1
• 3 (end of #2)
• 8 (start of #3)
• Integer.MAX_VALUE (end of #1 and #3)

If the actual agent version is 7, we should use a style sheet that matches #1, but not #2 or #3. However, we since we only use the start/end points of each version range to determine which style sheets to pregenerate, we fail to pregenerate such a style sheet.