Fixing errors

Author: rajithv

lib/symengine/complex.rb

@@ -1,7 +1,7 @@
 module SymEngine
   class Complex
     def to_c
-        self.to_s.sub('I', 'i').sub('*','').gsub(' ','').to_c
+        to_s.tr('I', 'i').tr('*','').tr(' ','').to_c
     end
   end
 end 

spec/complex_spec.rb

@@ -1,5 +1,5 @@
 describe SymEngine::Complex do
-  context '#initialize' do
+  context 'Convert to SymEngine types' do
     context 'with a Complex' do
       subject { SymEngine(Complex(2, 3)) }
 

spec/rational_spec.rb

@@ -1,5 +1,5 @@
 describe SymEngine::Rational do
-  context '#initialize' do
+  context 'Convert to SymEngine types' do
     context 'with a Rational' do
       subject { SymEngine(Rational('2/3')) }