Re-use regular expressions when parsing IEV termlinks

[skalee]

Initializing regular expressions over and over again takes almost 20% of concept generation time, not mentioning additional work for the garbage collector. Some easy improvement to do here, I guess.

[skalee]

Regular expressions in Ruby are generally immutable. I bet these two are root of all evil:

iev-data/lib/iev/termbase/term_builder.rb

Lines 396 to 397 in 4b2c0a9

	gsub(Regexp.new([SIMG_PATH_REGEX, "\\s*", FIGURE_TWO_REGEX].join('')), "image::/assets/images/parts/#{part_number}/\\1[Figure \\2 - \\3; \\6]").
	gsub(Regexp.new([SIMG_PATH_REGEX, "\\s*", FIGURE_ONE_REGEX].join('')), "image::/assets/images/parts/#{part_number}/\\1[Figure \\2 - \\3]").

I suppose they can be generalized so that they don't include any particular IEV domain, and so that they don't need to be reinstantiated over and over again.