#487 Add command line arguments to support web page load/save feature

[Ken Monks]

Add two command line arguments to Lurch to allow it to open or save a document from a web page. To open from a web page the argument might be something like

{{{./Lurch --openURL <url>}}}</url>

Which will open a new document in Lurch and do the equivalent of choosing {{{"File>Open from web page..."}}} from the Lurch menu if passed that <url>.</url>

To convert a Lurch document to html from the command line, there should be two arguments something like

{{{
./Lurch --to-html-fragment <filename>.lurch
./Lurch --to-html-page <filename>.lurch
}}}</filename></filename>

which will put the appropriate html on {{{stdout}}}. Thus if you want to convert a library of .lurch files to a set of complete html pages you can easily save them to a different folder in your script that loops through the files.