[announce/2015.04.md] add a list of changes

Note that this is a subset of all the things from the ChangeLog.
This month there were a lot of things, and we show the most notable
ones.

docs/announce/2015.04.md

@@ -16,7 +16,19 @@ Vladivostok, because we've run out of .pm groups in China.
 
 Some of the changes in this release are outlined below:
 
-TBD
+* Installation directory layout changed: it now uses $PREFIX/share instead of
+   $PREFIX/languages
+* "0" (0 as a string) is now True, no special-casing anymore
+* an Int() coercion type in a multi now creates two candidates: Any and Int
+* numerous small fixes
+* native arrays
+* 'bit' and 'byte' native types
+* starts-with/substr-eq/ends-with for comparing strings inside other strings
+* basic implementation of Uni, NFC, NFD, NFKC, and NFKD on Moar backend
+* where constraints on variable and attribute declarations
+* 'is rw' parameters implemented for native subs (they get passed as a pointer)
+* Str.codes/chars/uc/lc/tc/tclc/ord/flip about 25% faster
+* many smaller speedups
 
 These are only some of the changes in this release. For a more
 detailed list, see "docs/ChangeLog".