Relocate source fiiles to src/ subdirectory

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

Makefile.am

@@ -1,23 +1,9 @@
 ACLOCAL_AMFLAGS     = -I m4
 
-lib_LTLIBRARIES     = libuev.la
-libuev_la_SOURCES   = uev.c io.c timer.c signal.c cron.c
-libuev_la_CPPFLAGS  = -D_GNU_SOURCE -D_TIME_BITS=64
-libuev_la_CFLAGS    = -W -Wall -Wextra
-libuev_la_LDFLAGS   = $(AM_LDFLAGS) -version-info 1:2:0
-
-noinst_PROGRAMS     = bench
-bench_CPPFLAGS      = -D_GNU_SOURCE
-bench_LDADD         = libuev.la
-
-pkgconfigdir        = $(libdir)/pkgconfig
-pkgincludedir       = $(includedir)/uev
-pkgconfig_DATA      = libuev.pc
-pkginclude_HEADERS  = uev.h private.h queue.h
 doc_DATA            = README.md LICENSE
 EXTRA_DIST          = README.md LICENSE AUTHORS ChangeLog.md
 DIST_SUBDIRS        = examples tests
-SUBDIRS             = tests
+SUBDIRS             = src tests
 
 ## Generate .deb package
 package: