Fix handling of Skip and Start parameters

The way we treated Skip and Start parameters was inconsistent and wrong.
In some calls we send both parameters (s, start, S). This causes
and undefined behaviour at Gerrit itself.

Additional the Skip/Start parameters are numbers and not strings.
Here we fixed the Go types.

Thanks a lot to @michaeldorner for his initial work in #48

Related:
- #48

Author: andygrunwald

changes.go

@@ -518,8 +518,7 @@ type QueryOptions struct {
 type QueryChangeOptions struct {
 	QueryOptions
 
-	// The S or start query parameter can be supplied to skip a number of changes from the list.
-	Skip  int `url:"S,omitempty"`
+	// The `S` or `start` query parameter can be supplied to skip a number of changes from the list.
 	Start int `url:"start,omitempty"`
 
 	ChangeOptions

projects.go

@@ -170,8 +170,8 @@ type ProjectBaseOptions struct {
 	// Limit the number of projects to be included in the results.
 	Limit int `url:"n,omitempty"`
 
-	// Skip the given number of branches from the beginning of the list.
-	Skip string `url:"s,omitempty"`
+	// Skip the given number of tags from the beginning of the list.
+	Skip int `url:"S,omitempty"`
 }
 
 // ProjectOptions specifies the parameters to the ProjectsService.ListProjects.
@@ -192,9 +192,6 @@ type ProjectOptions struct {
 	// For example: the regex 'test.*' will match any projects that start with 'test' and regex '.*test' will match any project that end with 'test'.
 	Regex string `url:"r,omitempty"`
 
-	// Skip the given number of projects from the beginning of the list.
-	Skip string `url:"S,omitempty"`
-
 	// Limit the results to those projects that match the specified substring.
 	Substring string `url:"m,omitempty"`
 

projects_branch.go

@@ -32,7 +32,7 @@ type BranchOptions struct {
 	Limit int `url:"n,omitempty"`
 
 	// Skip the given number of branches from the beginning of the list.
-	Skip string `url:"s,omitempty"`
+	Skip int `url:"S,omitempty"`
 
 	// Substring limits the results to those projects that match the specified substring.
 	Substring string `url:"m,omitempty"`