Add error to CMakeList.txt on missing Boost. Fix if sample

CMakeLists.txt

@@ -19,5 +19,7 @@ if (Boost_FOUND)
 	#add_executable(dispatchkit_test contrib/test/dispatchkit_test.cpp)
 	target_link_libraries(chaiscript_eval ${Boost_LIBRARIES})
 	install(TARGETS chaiscript_eval DESTINATION ${CMAKE_CURRENT_SOURCE_DIR}/bin)
+else(Boost_FOUND)
+        message(FATAL_ERROR "Can not find Boost")
 endif(Boost_FOUND)
 

samples/if.chai

@@ -2,7 +2,7 @@ var i = 0
 if (i == 0) {
 	print("i is 0")
 }
-elseif (i == 1) {
+else if (i == 1) {
 	print("i is 1")
 }
 else {