More work on renaming functions. Change long string syntax to use

backticks. Allow custom masks in fibers for custom error and debug
handling.

examples/assembly.dst

@@ -1,7 +1,7 @@
 # Example of dst bytecode assembly
 
 # Fibonacci sequence, implemented with naive recursion.
-(def fibasm (asm/asm '{
+(def fibasm (asm.asm '{
   arity 1
   bytecode [
     (ldi 1 0x2)         # $1 = 2

examples/lazyseqs.dst

@@ -2,7 +2,7 @@
 # sequences, as in clojure. The lazy seq is essentially
 # A lazy linked list, where the next value is a function
 # that must be called (realizing it), and the memoized.
-# Use with (import "./path/to/this/file" :prefix "seq/")
+# Use with (import "./path/to/this/file" :prefix "seq.")
 
 (defmacro delay [& forms]
  "Lazily evaluate a series of expressions. Returns a function that