Upstream the clr-boot-manager features

[ikeydoherty]

clr-boot-manager has a whole bunch of really nice APIs, which should be in libnica itself

Notably:

• CbmWriter - a failsafe memstream based stream writer ✓
• CbmMappedFile - a very simple mechanism for working with mapped files (with autofrees) ✓
• File manipulation functions (atomic copies, etc) ✓
• A trivial log mechanism (expand this to be libraryfied) ✓
• Better string functions (string_printf) ✓

Perhaps:

• Filesystem APIs which allow overriding the process-space vtable for all file ops? Enables easy, safe mocking (would be nice)
• Port the cmdline reader into a generic config reader? Especially with the *.d/*.conf support (very low priority, ideally just nice "read this thing" APIs) (meh. maybe)

[ikeydoherty]

@bryteise wouldn't mind your thoughts on this :)

[bryteise]

I like the idea of the API providing a file ops vtable. Kind of a pain to write yourself every time you want to do something.

The commandline reader is also not a bad one but I'd wait until there are a few example applications doing git/ip style subcommands first.

The rest is pure steal it now please.

[ikeydoherty]

Sure, I'll keep the coverage up in our submodule, and then we can drop our versions from CBM, which in turn should balance the coverage out over there too :]

[ikeydoherty]

OK I've annotated the initial issue to indicate whats what :)